The present invention relates to a mobile communication system for forecasting communication-traffic generated by communication terminals mounted in the vehicles on a road. In a system for suitably assigning a radio resource, such forecasted communication-traffic information will be very effective. In particular, the present invention relates to ITS (Intelligent Transportation System).
In response to recent widespread use of mobile communications, the communication-traffic required for the service of the mobile communication is increasing abruptly. Conventionally, the services provided by the cellular systems or the PHS systems were only a voice service or a character service because the transmission rate in the system was very low.
In the next generation mobile communication system such as ITS or IMT-2000, however, the transmission rate becomes high, and thus the system can provide various services including image service. Particularly in ITS, the vehicle-mounted terminal can provide a large screen to present various image services including the existing navigation information service.
In the ITS, various communication-traffic such as the automatic running control information of vehicles will occur, control information required for the communication service, and general video image data and voice information. Furthermore, the amount of required communication-traffic changes due to various factors such as traffic-congestion status, road statuses (curves, tunnels, road slopes, accidents, etc.) or weather statuses.
In the ITS, cells are arranged linearly along the road, not two-dimensionally. Communications are executed between an antenna base station in each cell and vehicle-mounted terminals. However, in a DSRC (Dedicated Short-Range Communications) system which is one of communication systems between road-side radio communication system and vehicles, the distance between cell base stations is quite shorter than that of the cellular system. Generally, if a service area covered by one base station becomes large, the communication-traffic to the base station will increase and thus the large grouping effect will is obtained. Therefore, in this case, no strict forecast of the communication-traffic is necessary.
However, in case of the ITS, since the distance between the cell base stations is short, it is required to finely forecast the communication-traffic and thus improved communication quality service can be expected. In addition, extra radio resources are not provided to each station, because of the fine forecast results, therefore efficient usage of the radio resource can be attained. Furthermore, since the communication-traffic is forecasted suitably, the load of the radio resource control system can be decreased.
However, according to the conventional art, the communication-service provider forecasted the communication-traffic for each cell only from the past communication-traffic in the cell. Therefore, it was very difficult to accurately forecast the communication-traffic changed in response to various factors such as transportation-traffic or road-traffic.
It is therefore an object of the present invention to provide a mobile communication system for accurately forecasting communication-traffic changed in response to various factors such as transportation-traffic.
According to the present invention, a mobile communication system has exchange units for exchanging communication-traffic among mobile terminals, a transportation-traffic monitor for detecting transportation-traffic of the mobile terminals, and a traffic forecast unit including at least a communication-traffic forecast unit for forecasting future communication-traffic based on the detected communication-traffic and on the detected transportation-traffic.
The communication-traffic that will be changed due to various factors such as transportation-traffic can be exactly forecasted by using transportation-traffic information. The exact forecast of communication-traffic will provide suitable allocation of radio resources resulting effective usage of frequency spectrum. Also, since the radio resources are suitably allocated, the load of the system for controlling radio resources can be mitigated. Furthermore, even in the next generation communication system such as ITS which needs fine forecast of communication-traffic, it is possible to provide improved communication services.
It is preferred that the exchange unit detects communication-traffic of each mobile terminal class, and the transportation-traffic monitor detects transportation-traffic of each mobile terminal class, that the traffic forecast unit further includes a multivariate analysis unit for calculating communication-traffic of each element by multivariate-analyzing the detected communication-traffic, and a transportation-traffic forecast unit for calculating future transportation-traffic of each element based on the detected transportation-traffic, and that the communication-traffic forecast unit calculates future communication-traffic based on a relational expression of multivariate analysis with calculated future transportation-traffic of each element. The relational expression is obtained from a relationship between now and past transportation-traffic of each element and now and past communication-traffic of each element. Since communication-traffic is forecasted for each element, sufficient amount of information for forecast can be obtained resulting the reliability of the forecast to be improved.
It is preferred that the element is a principal component, a factor or a cluster, and that the multivariate analysis unit analyzes the principal component, the factor or the cluster with respect to communication-traffic of each mobile terminal class.
It is preferred that the exchange unit detects and outputs communication-traffic of each mobile terminal class, and the transportation-traffic monitor detects and outputs transportation-traffic of each mobile terminal class, that the traffic forecast unit further includes a transportation-traffic forecast unit for forecasting future transportation-traffic of each mobile terminal class based on the detected transportation-traffic, and that the communication-traffic forecast unit calculates future communication-traffic based on a relational expression and on the future transportation-traffic of each mobile terminal class calculated by the transportation-traffic forecast unit. The relational expression is obtained from a relationship between now and past transportation-traffic of each mobile terminal class and now and past communication-traffic of each mobile terminal class.
It is preferred that the traffic forecast unit further includes a transportation-traffic forecast unit for forecasting future transportation-traffic based on the detected transportation-traffic, and that the communication-traffic forecast unit calculates future communication-traffic based on a relational expression and on the future transportation-traffic calculated by the transportation-traffic forecast unit. The relational expression is obtained from a relationship between now and past transportation-traffic and now and past communication-traffic. Thus, the present invention can be applied to a case where the mobile terminal class is not stored in the radio interface for a communication or to a case where the exchange unit has no function for detecting the communication-traffic of each mobile terminal class.
It is preferred that the communication-traffic forecast unit calculates future communication-traffic based on a relational expression. The relational expression is obtained from a relationship between past transportation-traffic and now and past communication-traffic. Thereby, the system can be constituted simplest.
It is preferred that the mobile terminal class of communication-traffic includes a class of a vehicle with the mobile terminal, and a class of an area within which the mobile terminal exists, and a class of communication service provided for the mobile terminal, and that the mobile terminal class of transportation-traffic includes a class of a vehicle with the mobile terminal, and a class of an area within which the mobile terminal exists.
It is preferred that the transportation-traffic forecast unit and/or the communication-traffic forecast unit use time-series forecast scheme.
It is preferred that the system further has a forecast model renewal unit for updating a forecast model of communication-traffic in the relational expression, based on actual communication-traffic, the forecast model renewal unit cooperating with the communication-traffic forecast unit.
It is preferred that the system further has a forecast model renewal unit for updating a forecast model of transportation-traffic in the relational expression, based on actual transportation-traffic, the forecast model renewal unit cooperating with the transportation-traffic forecast unit.
It is preferred that the system further has a transportation-traffic database for storing past transportation-traffic, and a communication-traffic database for storing past communication-traffic, and that the communication-traffic forecast unit forecasts future communication-traffic based on the stored information of change.
It is preferred that the system further has a road-information acquisition unit for storing road status information including information of curves, tunnels, road slopes and accidents, and a weather-information acquisition unit for storing weather status information, and that the communication-traffic forecast unit forecasts the future communication-traffic based on the road status information and the weather status information.